We’ve explored the ELK Stack, its power — and, unfortunately, its licensing changes. These changes sparked debate within the open-source community and led to the creation of a worthy alternative — OpenSearch.

OpenSearch is a fully open-source fork of the last open versions of Elasticsearch and Kibana, released under the Apache 2.0 license. The project was initiated by Amazon Web Services (AWS) in 2021 and has since evolved as an independent open-source initiative under the OpenSearch Project.

What Is OpenSearch and What Are Its Components?

OpenSearch mirrors the architecture and logic of the ELK Stack:

1. OpenSearch — a fork of Elasticsearch. A scalable search and storage engine designed for log and time-series analytics.
2. OpenSearch Dashboards — a fork of Kibana. A user interface for visualizing and analyzing data stored in OpenSearch.

How Does OpenSearch Work?

The data flow is nearly identical to ELK Stack:

1. Collection — agents (e.g., Filebeat or Logstash) send logs.
2. Processing — Logstash (or another tool) parses and enriches the logs.
3. Storage — data is indexed in OpenSearch.
4. Visualization — OpenSearch Dashboards allows dashboarding, querying, and trend monitoring.

Advantages of OpenSearch

• Fully Open Source — Apache 2.0 license, no hidden paid features.
• Elasticsearch API Compatibility — migration is as smooth as possible.
• Community-driven development — open, transparent growth; AWS is the lead, but not the only contributor.
• Security and alerting included for free — unlike Elastic Stack, key features come bundled.
• Inherited search and visualization power — the same experience as Elasticsearch + Kibana.

Drawbacks of OpenSearch: What to Watch For

• Ecosystem fragmentation — some plugins and tools may not work across both stacks.
• Elastic Stack may lead in features — Elastic often introduces new features before they appear in OpenSearch.
• Resource consumption — hardware requirements remain similar to Elasticsearch.
• Relative youth — while built on a mature base, OpenSearch has only been around since 2021.

Who Should Use OpenSearch?

• Teams looking for a true Open Source alternative to the ELK Stack.
• Teams that need security and alerting without extra cost.
• Organizations seeking vendor-neutral logging and analytics.

Unique OpenSearch Features (Free)

• Built-in security — encryption, access control, and audit logging.
• SQL and PPL support — query logs and metrics with familiar syntax.
• Alerting — define rules and triggers based on log data.
• Anomaly Detection — detect unusual patterns in real-time data streams.

Conclusion

OpenSearch is a powerful and mature alternative to the Elastic Stack. It retains the core strengths of ELK while removing the constraints of a commercial license. It’s a solid choice for anyone who values control, flexibility, and full openness in logging and data analytics.

In the next article, we’ll explore Graylog — a comprehensive and user-friendly centralized logging system with a strong focus on access control and security.